Lorien - I once had a student like this guy. Henry was a brilliant man, and so stiff I thought he'd snap like peanut brittle. What I've found is that in a case like this, don't do anything covert. I would actually say to this student like this, "Henry. Your attacks are still terrible, and they are going to take some time to develop. One of the problems this creates is that practicing with you can be aggravating to some people, because they want to work against a more effective attack. But we want you to learn as well. So until your attacks are as good as the brown belts, you are going to work in groups of three - that way you can gain skills at your rate of speed and work with others to do so, and they can help - and also work at the rate of speed they need to as well."

In my experience, folks on the spectrum of behavior that is being described here are not offended, as they tend to see the world in very logical terms. It's only the "sensitive souls," looking to be aggrieved by something as a means of getting social power thereby, who would claim to be stigmatized by working in a group of three.